1. Technical Field
The present disclosure relates to a sewing machine provided with a thread wiper which is actuated for securement of an amount of thread immediately before the cutting of a needle thread by a thread cutting mechanism so that a predetermined amount of needle thread located downstream relative to a needle eye of a sewing needle is secured.
2. Description of the Related Art
When workpiece cloth is sewn by various types of sewing machines, it has been conventionally ideal that a needle thread is prevented from dropping out of a needle eye and moreover, an end of the needle thread is prevented from remaining on an upper side of the workpiece cloth. Various types of sewing machines have been proposed which prevent the needle thread from dropping out of the needle eye or the end of the needle thread from remaining at the upper side of the workpiece cloth.
JP-A-2004-290293 discloses a sewing machine including a picker for retaining a needle thread. The picker is provided in front of a rotary hook provided in a front end of interior of a cylinder bed. The picker is pivotable over a needle thread retaining position, a standby position and a retreated position. The picker is designed to be switchable so as to be moved to the three positions via a linking member coupled to a picker driving motor. In the disclosed sewing machine, the picker is switched to the needle thread retaining position when the needle thread is cut. As a result, the needle thread engages the picker so that a predetermined amount of remaining thread can be secured.
JP-A-H08-57181 discloses a thread cutter for sewing machines including a movable cutting blade which is moved from a standby position to a pivot position (a first half of reciprocal movement) in cutting a thread so that a needle thread and a bobbin thread at the workpiece cloth side engage the movable cutting blade. The timing of returning movement of the cutting blade (a second half of the reciprocal movement) is changed in synchronization with rise of a thread take-up, that is, retarded so that an amount of remaining needle thread after thread cutting is adjustable, whereupon no picker is necessitated.
In the sewing machine disclosed by JP-A-2004-290293, however, the front end of the cylinder bed is extended to the distal end side since the picker is disposed in front of the rotary hook. Accordingly, the distance from the sewing needle to the cylinder bed is increased, whereupon a sewable area is narrowed in the cross direction in the case where an embroidery is sewn on a cap. Furthermore, since the picker driving motor is necessitated as well as the picker and the linking member, the size of the cylinder bed is increased. The production cost of the sewing machine is increased since the number of components is increased.
Additionally, although no picker is necessitated in the thread cutter disclosed by JP-A-H08-57181, an amount of remaining needle thread depends upon the synchronization of rise of the thread take-up with the timing of the second half of reciprocation of the cutter blade. As a result, an amount of remaining needle thread tends to be adversely affected by the material of workpiece cloth or needle thread.